Dried distillers grains with solubles (DDGS) are the co-products of bioethanol production, primarily from corn in the U.S. Traditionally, they have been viewed as animal feed, valued for their protein, fiber and energy content. However, their composition and processing suggest they can also be classified differently: as functional food postbiotics.
Functional foods are defined as foods that provide health benefits beyond their basic nutritional content, often through bioactive peptides, fibers, phytochemicals or microbial components. Postbiotics, in turn, are preparations of non-viable microorganisms and their cellular components that still exert biological activity in the host.
Because the fermentable carbohydrates in the grain are largely consumed during ethanol fermentation, the resulting co-product is rich in proteins, fiber, lipids, minerals and yeast biomass.
During drying, the microbial population, mainly Saccharomyces cerevisiae, is inactivated, leaving behind cell wall fragments, mannans, beta-glucans and peptides that can influence immunity and gut health. Thus, DDGS are not only nutritional residues but also carriers of microbial products with potential bioactive properties.
Composition and processing of DDGS
The most striking feature of DDGS is their carbohydrate profile. During ethanol production, yeast consumes the starch fraction of the grain, converting glucose into ethanol and carbon dioxide. This process removes most fermentable carbohydrates. As a result, corn based DDGS typically contain less than 8% starch on a dry matter (DM) basis, with total sugars often less than 2%. Total sugars are in the range of 1% to 2% DM, compared with more than 70% starch in the original grain. Instead of sugars, the carbohydrate fraction is dominated by non-starch polysaccharides, primarily cellulose, hemicellulose and arabinoxylans.
Continue reading this article published in Progressive Dairy.
